This invention is directed to flame-resistant, room-temperature vulcanizing silicone rubber compositions. More specifically, this invention is directed to the enhancement of the self-extinguishing properties of flame-resistant, room-temperature vulcanizing silicone rubber compositions.
Room temperature vulcanizing silicone rubbers (RTV) are well-known in the art. It is further known that such silicone rubbers can be made flame-resistant. For example, in Kokai Patent Gazette No. Sho 48 (1973)-64139, there is shown a method in which halogenated organic compounds are added to silicone compositions to enhance the flame resistance but these materials are deficient because they tend to give off toxic gases when burned due to the presence of the halogenated organic compounds. Kokai Patent Gazette No. Sho 48 (1973)-92452 shows a method in which platinum compounds are added to silicone compositions but it is shown by testing that platinum addition alone is not sufficient to impart adequate flame-resistance to silicone compositions. Further, it has been shown in Kokai Patent Gazette No. Sho (1973)-20839 that a combination of carbon black, platinum compounds and certain metallic oxides provide flame resistance to silicone compositions but they do not impart high enough flame resistance due to low self-extinguishing characteristics.
For the above reasons, there has been a demand for room-temperature vulcanizing, fire-resistant, self-extinguishing silicone compositions. This demand has been primarily from the electric and electronics industries and in the construction business.
This invention, therefore, offers a room-temperature vulcanizing silicone rubber composition which does not have the problems associated with the prior art compositions and which has in addition excellent self-extinguishing characteristics.